The data are summarized in Table 1 for all patients and according to the number of arterial grafts used. Multiarterial grafting was performed in younger patients, more in men, less in patients with significant heart failure defined as NYHA class ≥ 2 and in patients with left ventricular dysfunction and impairment of ejection fraction. Finally, one arterial graft (ITA) was used in 969 patients, two arterial grafts in 1883 patients (BITA: 1644; SITA+GEA: 239), and three arterial grafts in 833 patients (BITA+GEA). In multiarterial groups, complete revascularization was higher, sequential ITA graft and associated GEA were more frequent, and associated vein graft less. Interestingly, in the 2716 patients who received at least two arterial grafts, a vein graft was associated in 22% of cases, mainly as a complement to BITA in alternative to GEA when it was not suitable. Totally, 795 patients had one DAA, 1142 patients had two DAA, 1337 patients had three DAA, and 411 patients had at least four DAA.
Early results. In this series the early mortality was 1.6 % and it was not significantly influenced by the number of arterial grafts (Table 1), the number of ITA used (SITA, 1.9 %; BITA, 1.4 %; p=0.115) or the number of DAA performed (one DAA, 2.6 %; two DAA, 1.8 %; three DAA, 0.9 %; and at least four DAA, 1.2 %, p=0.054). The main postoperative complications are summarized in Table 2; the rate of reoperation for bleeding was significantly higher in multiarterial grafting. The rate of mediastinitis was significantly higher in diabetic patients (1.5 % vs 0.4 %, p<0.001) and in case of bilateral ITA grafting (0.8 % vs 0.1 %, p=0.023), to reach 2% in diabetic patients undergoing BITA (p=0.007). There was no difference in early cardiac death according to the graft configuration.
Long-term results. The mean postoperative follow-up was 13.1±7.3 years and 92% complete: 2021 late deaths (56%) occurred (mean delay 11±5 years), 1310 patient (36%) were alive (mean follow-up 17±6 years) and 295 patients (8%) were lost of follow-up, mainly foreign citizens (112 patients during the first postoperative year, and 183 patients after 7.7±4.2 years). Several preoperative and intraoperative variables were identified as significant risk factors of all causes mortality by univariable analysis: age, gender, heart failure, LV ejection fraction, diabetes status, complete revascularization, number of arterial grafts, number of DAA, both ITA, sequential ITA graft, GEA graft (Table 3); however, the mortality was not affected by the 3-vessel disease status and the use of an associated vein.
Long-term survival. Long-term survival was significantly better in multiarterial grafting (Figure 1, p=0.0001). In multivariable analysis with Cox regression model (Chi-square 962,298, df 8, p=0.0001), previous preoperative clinical variables remained independent risk factors of survival. Regarding operative and technical criteria, only the number of DAA was a significant independent prognosis factor of survival; complete revascularization and number of arterial grafts were not identified as independent prognosis factors (Table 4). BITA and GEA graft were found linearly dependent covariates with the number of arterial grafts, and sequential ITA with the number of DAA; these dependent covariates were introduced separately in the Cox model with consistent results: as the number of arterial grafts, BITA and GEA graft were not independent prognosis factor of survival, and sequential ITA was contributing significantly to the influence of the number of DAA on survival (Table 4). The impact of the number of DAA on survival was found significantly discriminant from 1 to 3 (Figure 2, p=0.0001). After 3 DAA, there is no more additional effect: the 5-, 10-, 15-, 20- and 25-year survival were respectively 91±2, 77±2, 62±3, 47±3, 30±4 in the 1337 patients who had 3 DAA and 91±3, 77±4, 62±5, 46±6, 32±7 in the 411 patients who had at least 4 DAA (p= 0.433).
Sub-group analysis. A sub-group analysis was done in the 2104 patients with 3-vessel disease who received at least 2 arterial grafts with in mean 2.9±0.7 DAA by patient. They represent 57 % of all the population and 79 % of the 3-vessel disease patients. In univariable analysis, gender was no more identified as prognosis factors of mortality; complete revascularization, number of DAA and sequential ITA had a significant impact on survival without influence of the grafts used (Table 3). In multivariable analysis with Cox regression model (Chi-square 568,364, df 8, p=0.0001) the number of DAA remained a significant independent prognosis factor of survival, predominant over complete revascularization and number of arterial grafts (Table 4); the impact of the dependent covariates was found unchanged. In this sub-group of patients, the impact of the number of DAA on survival was found significantly discriminant between 2 and 3 (p=0.0001), and low and non-significant (p=0.406) between 3 and at least 4 (Figure 3).